1. Field of Invention
The present invention relates to a breast pump for lactating women, and more particularly to a suction device in a piston-type breast pump.
2. Description of Related Arts
Manual breast pumps are divided into two types, the membrane type or the piston type. The membrane type has a simple structural construction and is easy to use. However, the drawbacks include a short stroke for the process, low suction force and requiring manual operation using fingers to providing pulling and pushing or squeezing force adequate for creating an vacuum condition and causing tiredness of users fingers. Piston-type breast pump has the advantages of greater stroke for the process, higher suction force and providing a relative closer simulation effect to a suction frequency of a baby. However, this type of breast pump also requires direct pulling and pushing and great pulling force is necessary which may cause tiredness of users fingers. After delivery, a mother will become very sensitive to tiredness of fingers and therefore a manual breast pump, which is of low frequency, high suction and high efficiency but does not require finger's operation for providing the pulling and pushing or squeezing force is needed.